Rear disc running very hot
 

I have noticed the rear disc is very hot even if I stay off the rear brake, what can cause this on the 916.
I've bled it and the pistons don't appear to be sticking but they are bone dry, would a little copper grease help em retract or what.

Thanks for your reply you font of all knowledge. :burn:

I had that hapen to me I found that although I wasn't using the rear brake I was resting my foot on it put a bit more free play in it, worked for me.

Chass

Dont put copper grease on the pistons, you need special brake grease.

chass i'll give it a go :eureka:

rockhopper how "special" :ninja:

erm, something in a tin labled "brake grease"!! Its got to be safe on the rubber seals. Copper grease contains tiny bits of copper so you shouldnt use it on moving parts as it'll wear them away!

I'll be buggered "brake grease" why dint I think o that.

If it's that red stuff we've got it at work, but i'll buy me own of course :pig:

Couple of thoughts would be that the resevoir is over filled or possibly that you need to rebuild the calipers and master cylinder.

I'm gonna strip it down and clean everything, I've been told they don't sell the seals though ?

A new caliper is only £60 right ?

£69.72 including the VAT from On Yer Bike . Remember the heat from the Exhaust does get the master cylinder reasonable hot and if the fluid resovior is to full stops any expansion. Also, the adjusting rod that fits into the rubber grommet on the master cylinder it should be able to be withdrawn enough to allow the fluid to return back through the seal plunger. I had too replace 2 calipers within a month because of this . So dont try to have to little rear brake travuss on the foot lever. There do not sell parts only for Brembo brakes . 4D

[Edited on 30-5-2005 by Fordie]

Happened to me - the rear master cylinder was knackered - the pedal wasn't returning properly - ended up costing me a disc, caliper and master cylinder. New seals/master cylinder should cure it.

I have this on my 600 monnie, thought the brake is stickin on but doenst seem to be, but is does squael a bit when stopping...any clues?

Just had the same on my 748R. Resulted in me replacing the pads (which are part of the caliper) and a disc.

Think the caliper was also available from Spondon Engineering, about £50 + vat and is brembo.

Have been told that is fairly common, if that makes you feel any better...

Yep, I've got this on my ST as well.

Since I never, ever, never, ever use the back brake I don't even bother bleeding it until MOT time. The MOT was last week and now my back brake is sticking on.

Could be that I've overfilled the reservoir when bleeding the brake or it could be that, since I never use it, the pistons are just stuck. Either way I don't think it's anything that a good clean and grease up can't fix.

Plenty to go at there thanks.
I've been doing the garden for three days but I'll sort the bike before Croft on sunday.
See ya there:burn:

I had this problem on an ST2. Once you get into the loop of overheated rear brake it is hard to sort it because the following tends to happen:

Boil the fluid with heat passed back through the caliper
Heat buckles the disk causing small amout of friction
The heat build up causes the fuild to heat up and expand - if it is overfull then it has no where to go and the pads squeeze the disk enough to increase the heat, etc etc.

I'm sure you problably get the picture.

As for cleaning the pistons, I was also told a little brake fluid on a clean rag was the way to go. Shouldn't need grease, and definately not copper grease. The red stuff you refer to sounds like "Red Rubber Grease" and is worth having a tin of around. Our local dealer uses that for everything from electrics to 749/999 coil seals to well nuts - it's pretty safe. Not sure about how it might react with brake fluid on the pistons though.

Thinking about it - remove the caliper from the wheel and push the pistons out a little. Be careful not to push one ALL the way out - it is possible I did it on the ST2 and a sod to get back in. Wipe around the piston before it goes back in then alternately lever them back in and use the brake lever to push them out again. Sometimes hard to get both to work because one will move easier than the other. That might be the problem then in fact, one sticking piston.

Hope some of that helps, and does not confuse too much. Head full of cold so I am rambling even more than usual! :sniff:

You mean the rear brake actually does something.................can't believe anyone really believes that. Last three 916/998's I've had you might as well have been stomping on a piece of wood for all the good it did!!!!

On the ST2 it certainly did something ... I ended stopped at the side of the road wondering why I could not move.